U.S. patent application Ser. No. US 2002/0013772 and International patent applications no. WO00/58811 and no. WO00/59150 (all emanating from U.S. provisional application 60/126,614) disclose ways of distributing and binding a digital licence to a user device using Digital Rights Management (DRM). A DRM system operates on a computing device when a user requests a digital piece of content to be rendered by the computing device. The system has a license store, a licence evaluator, and a state store, and keeps track of possible content rendering. The digital content is encrypted according to a content key (KD) on a user device having a public key (PU) and a corresponding private key (PR). To render digital content a digital licence corresponding to the content is obtained, where the digital licence includes the content key (KD) therein in an encrypted form. The encrypted content key (KD) from the digital license is decrypted to produce the content key (KD), and the public key (PU) of the user device is obtained there from. The content key (KD) is then encrypted according to the public key (PU) of the user device (PU(KD)), and a sub-license is composed corresponding to and based on the obtained license, where the sub-license includes (PU(KD)). The composed sub-license is then transferred to the user device, wherein the user device can decrypt (PU(KD)) with the private key thereof (PR) to produce the content key (KD), and can render the encrypted content on the user device with the produced content key (KD).
The disclosed system requires a separate license for each computing device ordering a particular digital content, thus effectively limiting the fast distribution of content throughout a plurality of computing devices. Hence when a plurality of users request an identical content every user must have a separate licence.
International patent application no. WO01/98903 discloses methods and systems for distributing content via a network using distributed conditional access agents to perform DRM. These include a watermarking operation to watermark content distributed to a content consumer. Further, an encryption operation encrypts content using a key associated with the content consumer. The content provider generates a set of session keys, encrypts the content using the set of session keys, and communicates the session keys to a content distributor. The content distributor encrypts the set of session keys using a user key so as to generate a set of encrypted keys, which are subsequently communicated to the content consumer. The content distributor further communicates the user key to the content consumer, which upon receipt decrypts and extracts the set of session keys and uses the set of session keys to decrypt the encrypted content. The set of session keys can be a time-varying sequence of session keys. The process can include authentication and verification of the user credentials against content access criteria. As described above with reference to US 2002/0013772, WO00/58811 and WO00/59150 these systems and methods are directed to one user/one device concept.
The patent applications US 2002/0013772, WO00/58811, WO00/59150, and WO01/98903, which patent applications are incorporated by reference in present specification, introduce problems since users want to experience the same right with digital media as with conventional media.